Engineered three-dimensional scaffolds for enhanced bone regeneration in osteonecrosis

Abstract

Osteonecrosis, which is typically induced by trauma, glucocorticoid abuse, or alcoholism, is one of the most severe diseases in clinical orthopedics. Osteonecrosis often leads to joint destruction, and arthroplasty is eventually required. Enhancement of bone regeneration is a critical management strategy employed in osteonecrosis therapy. Bone tissue engineering based on engineered three-dimensional (3D) scaffolds with appropriate architecture and osteoconductive activity, alone or functionalized with bioactive factors, have been developed to enhance bone regeneration in osteonecrosis. In this review, we elaborate on the ideal properties of 3D scaffolds for enhanced bone regeneration in osteonecrosis, including biocompatibility, degradability, porosity, and mechanical performance. In addition, we summarize the development of 3D scaffolds alone or functionalized with bioactive factors for accelerating bone regeneration in osteonecrosis and discuss their prospects for translation to clinical practice.

Keywords: Bone regeneration; Bone tissue engineering; Functionalization; Osteonecrosis therapy; Three-dimensional scaffold.

Graphical abstract

Scheme 1

Engineered 3D scaffold for enhanced bone regeneration in osteonecrosis.

Fig. 1

Manufacture of 3D PLGA/TCP scaffold with excellent biocompatibility and biodegradability for bone regeneration in osteonecrosis [44,73]. (A) Porous PLGA/TCP (PT) and PLGA/TCP/Mg (PTM) scaffolds produced by 3D printing technology and their in vivo test [44]. (B) SEM (B1) and fluorescent microscope (B2) observation for attachment and morphology of BMSCs (arrows) seeded on scaffolds after 24 h and 15 days, respectively. T denotes trabeculae of scaffolds, and P denotes pores of scaffolds. Scale bar, B1 = 50 μm, B2 = 500 μm [73]. (C) Micro-CT images of the new bone formation and the residue of PT and PTM scaffolds in bone tunnel at each time point after surgery. Control group represents surgery without scaffold implantation. Scale bar = 1 mm [44]. Reproduced with permission [44]. Copyright 2019, Elsevier Ltd. Reproduced with permission [73]. Copyright 2012, John Wiley & Sons, Ltd.

Fig. 2

3D scaffolds with different porosities in different parts for enhanced bone regeneration in osteonecrosis [2]. (A) Graphic image shows how the three segments of FGS with different porosity were distributed in the femoral head. (B) Micro-CT showed that the scaffolds had three different porosity segments and excellent pore connectivity. (C) An external view of FGS with magnified view. Scale bar = 2 mm. (D) Micro-CT image of FGS-implanted group (FGS) and empty-tunnel group (ET) after drilling of rabbit femoral head. Drilled tunnel was indicated by a dashed line. Scale bar = 5 mm. (E1) Representative hematoxylin and eosin (H&E) staining observed new bone formation. S refers to scaffolds. Scale bar = 100 μm. (E2) Magnified image of the region depicted by a rectangle in E1. Blood vessels coexisting with osteon-like structures were indicated by arrows. Scale bar = 100 μm. Reproduced with permission [2]. Copyright 2017, John Wiley & Sons, Ltd.

Fig. 3

Role of 3D scaffolds with different mechanical performances in promoting bone regeneration in osteonecrosis [25]. (A,B) The compressive (A) and bending strength (B) testing results at 12 weeks after surgery. Normal means normal canine bone without osteonecrosis, Control means necrotic bone without therapy, DBM means treated necrotic bone by DBM, DBM/BMSCs means treated necrotic bone by DBM and BMSCs, Ad-BMP-2-bFGF-GFP means treated necrotic bone by DBM and BMSCs transfected with adenovirus vector plasmid containing BMP-2 and bFGF, and Ad-GFP means treated necrotic bone by DBM and BMSCs transfected with adenovirus vector plasmid. All P < 0.05 by Student-Newman-Keuls (SNK) method. (C) H&E staining images of the canine model at 12 weeks after surgery. Black arrow indicates trabecular bone. Scale bar = 100 μm.

Fig. 4

Combination of 3D scaffold with BMSCs for enhanced bone regeneration in osteonecrosis [38]. (A) SEM image after 21 days of co-culture of BMSCs with Bio-Gide® collagen membrane. Scale bar = 10 μm. (B) Image of BMSCs co-cultured with porous Ta scaffold observed by SEM after 21 days. Scale bar = 10 μm. (C) Toluidine blue staining at 12 weeks after surgery. Empty control refers to the full-thickness articular defect of femoral head without implantation, BT refers to the defect filled with 3D scaffolds composed of Bio-Gide® collagen and porous Ta, BBT refers to the defect filled with 3D scaffolds composed of BMSCs, Bio-Gide® collagen, and porous Ta, the black square was the enlarged area. Reproduced with permission [38]. Copyright 2019, Elsevier Ltd.

Fig. 5

Engineered 3D FGS combined with BMMCs decreased necrotic area and enhanced bone regeneration in osteonecrosis [48]. (A) H&E staining in each group. CD refers to core decompression only, FGS refers to CD and FGS filled in, BMMC refers to CD and BMMCs injected in, FGS/BMMC refers to CD, and functionalized FGS combined with BMMCs filled in. The red arrow denotes empty lacunae, and the black arrow denotes normal osteocyte. Scale bar = 200 μm. (B) Percentage of the empty lacunae in each group. Asterisk * indicates P < 0.05 by Dunn post-hoc test. (C) Micro-CT reconstructed images of the drill channel in femoral heads. Reproduced with permission [48]. Copyright 2018, 2018 Elsevier Ltd.

Fig. 6

Peptide-based hydrogel loaded with BMP-2 prevented ectopic ossification during management [33]. (A) The model was drilled and injected with functionalized hydrogel (B) Confocal microscopy images (20× magnification) showed the BMSC nuclei after 7 days of being cultured with tissue culture plastic (Control) or different concentrations of RADA16 (0.25%, 0.75%, and 1.5%) in vitro. (C) The micro-CT images showed the amount of backflow of the radiocontrast solution down the tunnel after being combined with the peptide-based hydrogel (RADA16) at different concentrations. The yellow outline indicates the tunnel inside the femoral head epiphysis, and the red arrow indicates the backflow of radioactive contrast outside the femoral head epiphysis. (D) Percentage of backflow of different concentrations of RADA16 in the tunnel. Asterisk * indicates the greater backflow compared with other test groups, P < 0.05 by Tukey's post-hoc test. Reproduced with permission [33]. Copyright 2016, American Chemical Society.

Fig. 7

BMP and VEGF dual-loaded 3D scaffolds for enhanced bone regeneration in osteonecrosis [40]. (A and B) ALP (A) and nitric oxide (B) activities in each group of BMSCs seeded after 7 and 14 days. The blank control group refers to cell culture with the cell culture plate, and the PLGA−CPC scaffold, BMP-PLGA−CPC scaffold, VEGF-PLGA−CPC scaffold, and BMP-VEGF-PLGA−CPC scaffold groups refer to cells cultured with the corresponding scaffolds. Asterisk * indicates P < 0.05 by Bonferroni's post-hoc tests. (C) The model of rabbits undergoing CD (C1) followed by the implantation of scaffolds into the bone defect (C2 and C3). (D) 3D reconstruction images of the femoral head by micro-CT showing newly mineralized tissue in each group in the 6^th week (D1−D5) and 12^th week (D6−D10). The C,D group refers to pure core decompression without implantation of scaffolds, and the PLGA−CPC scaffold, BMP-PLGA−CPC scaffold, VEGF-PLGA−CPC scaffold, and BMP-VEGF-PLGA−CPC scaffold groups refer to the implantation of the corresponding scaffolds. Reproduced with permission [40]. Copyright 2016, Elsevier Ltd.

Fig. 8

Icariin-loaded 3D scaffolds for enhanced bone regeneration in osteonecrosis [39]. (A) PLGA, β-TCP, and icariin were produced into 3D scaffolds (PTI) by low-temperature 3D printing technology and used for related studies in vivo and in vitro. (B and C) Changed compressive strength of 3D scaffolds (B) and icariin released (C) during in vitro degradation. Superscript symbol ^# indicates P < 0.05 and superscript symbol ^## indicates P < 0.01 by Bonferroni post-test. The PT group denotes only scaffolds, and PTI-L, PTI-M, and PTI-H denote scaffolds with icariin concentrations of 0.16%, 0.32%, and 0.64%, respectively. Superscript symbol ^$ indicates P < 0.05 and superscript symbol ^$$ indicates P < 0.01 compared with the PTI-H groups by Bonferroni post-test. (D) 3D reconstruction images of the distal femora showed the new bone formation in the defect at 2, 4, and 8 weeks after CD. Control refers to CD without implantation, and PT and PTI-M refer to CD with PT scaffolds and PTI-M scaffolds implanted. Reproduced with permission [39]. Copyright 2018, Elsevier Ltd.

Fig. 9

Combination of 3D scaffolds with Li and EPO for enhanced bone regeneration in osteonecrosis [59]. (A) Schematic of study design. (B) H&E staining images showed the bone repair at 6 and 12 weeks. Scale bar = 200 μm. (C) At 6 and 12 weeks after surgery, immunohistochemical staining of angiogenic factor VEGF (green) took place. The blank control group refers to creating the femoral head defect without implantation, and the nHA, Li-nHA, and Li-nHA/GMs/rhEPO groups refer to repairing the femoral head defect with the implantation of corresponding 3D scaffolds. Scale bar = 100 μm. Reproduced with permission [59]. Copyright 2018, Royal Society of Chemistry.